<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <script>
    var arr = ['刀仔', '萝卜头', '葫芦娃', '小明', '小灰灰', '毛毛', '卢本伟']
    
    // 随机生成一个索引
    // 0 ~ arr.length  包含0但是不包含arr.length
    var index = Math.floor(Math.random() * arr.length)

    console.log('下次' + arr[index] + '来给大家唱歌')

  </script>
</body>
</html>